Eight days ago I brewed a PM Tripel, using .5 lbs each of flaked oats, wheat and rye (1.5 total) along with 3 lbs of base malt. At the end of the mash (70 min @ 151) it was quite cloudy, and not as sweet as I remember previous ones being. I continued with the boil anyways, and was surprised to find that I had more or less hit my target gravity of 1.080. After some research, the cloudiness seems to have been due to unconverted starches from the flaked grains, as I did no protein rest.

Did those unconverted starches affect gravity in a significant way? For the last few days fermentation seems to have stalled (or finished?) around 1.022. I'm using Wyeast 3522 and I'd like to end up closer to 1.014 or drier, especially since the flaked grains have added a lot of body. Fermentation temps started at 67 and are up to 75.

The beer tastes very good, if a little too sweet, so I'm thinking there's something left for the yeast to eat. But could the gravity reading at this point be on account of starch?

Unconverted starches would be my bet for the cloudiness too. Without knowing exactly what grains you used, I can't say if I agree that the solution would have been to use a protein rest, or to use a cereal mash.

In other case, unconverted starches are not fermentable, so if that's your problem, then the yeast will not consume the remaining "sweetness." You might, however, be able to find an enzyme that will break down the starches and allow fermentation to complete? White Labs makes one called Ultra Ferm that would probably help.

(1) I think that unconverted starches add more of a breadyness than a true sweetness. . . but yes, that might be what you're tasting, especially if they were partially converted.

(2) Yes, unconverted starches are not fermentable by standard brewing yeast, so no matter how long you wait, they will never be eliminated. If your gravity eventually falls because of rousing the yeast, raising the temperature, or just more time, then it wasn't unconverted starches to begin with.

(3) Yes, they contribute to the gravity. EVERYTHING you put in your beer contributes to the gravity, regardless of whether it's fermentable or not. Here's an example: when you swim in the ocean, you float higher than in a freshwater pool. When you swim in the dead sea (which is REALLY salty) you float even higher than in the ocean. That's true because YOU operate just like a hydrometer. Saying you "float higher" is the same as saying that the gravity of the dead sea is higher than the gravity of freshwater. Or, put yet another way, salt - which is clearly not fermentable - will add to the gravity of your beer.

So, long story short, unconverted starches, like salt, silica gel, and anything else that dissolves in water, will increase your gravity.

I'm gradually raising the temp up to about 80. Maybe it is a sign that the yeast is still active in that the krauesen shows no sign of wanting to fall. Perhaps I'm just being impatient, but in the past all my beers of similar, and greater, size have attenuated within a week.

I may not have been clear, and I apologize. Quick oats, are partially gelatinized but they will still benefit from being cooked before hand, although it is not absolutely necessary. Flaked oats are those garbage instant oats at the grocery store, and I wouldn't eat them, much less put them in by beer.

Old Fashioned oats have not been pre-gelatinized and need to be cooked first as their gelatinization temperature is far below a typical mash temperature. I eat these for breakfast so this is what I use, and this is what my friends use as well. We make some pretty killer stouts if I don't say so myself.

Edit To the OP: what kind of oats did you use? Proper quick oats from the LHBS, or the Quaker Oat variety? If you went with the Quaker Oats, were they quick oats? Or old fashioned?